Apparatus and method for shredding insulation

ABSTRACT

The shredding apparatus comprises a shredder housing with an inlet having a flow regulator that feeds insulation into the housing at a selected rate. A blade assembly is positioned within the housing adjacent the inlet. The blade assembly rotates about an axis designating an insulation flow direction. The blade assembly has a plurality of knife blades that are arranged in a helix about the axis, and are operable to catch insulation fed from the flow regulator. A stator positioned adjacent the blade assembly obstructs the insulation caught on the blade assembly such that the blade assembly shreds the insulation. The blade assembly urges the shredded insulation to an auger positioned coaxially with the blade assembly that discharges the shredded insulation from the housing.

This application is a continuation, of application Ser. No. 08/210,515,filed on Mar. 17, 1994, now abandoned.

FIELD OF THE INVENTION

The present invention relates to an apparatus and method for shreddinginsulation, and more particularly, to an apparatus and method forshredding insulation into small pieces that may be blown into wallcavities and the like.

BACKGROUND OF THE INVENTION

Insulation is often produced in sheets that are rolled and shipped to abuilding construction site or the like. At the construction site, thesheets are unrolled and trimmed for installation into building wall andceiling cavities. Such trimming produces large amounts of scrapinsulation that is often discarded and dumped into landfills.

In spite of the inherent waste and expense of discarding scrapinsulation, there has been no practical way to recycle such scrapinsulation. For instance, existing machines for shredding insulationinto small pieces for use as "blow-in" insulation have not previouslyproved adaptable to the recycling of scrap insulation.

Such existing shredding machines are expensive, high-volume machinesdesigned only for producing blow-in insulation in insulation factories.One such a shredder uses a chain assembly to shred entire insulationsheets that are laid out flat. Another shredder has a large drum withcookie-cutter-type blades that rolls over entire laid-out sheets ofinsulation to cut the insulation into pieces.

Because of the expensive, high-volume design, such factory shreddingmachines are uneconomical to apply to sporadic recycling use. Moreover,factory shredding machines tend to be large and not easilytransportable.

SUMMARY OF THE INVENTION

The present invention is directed to an improved apparatus and methodfor shredding insulation. It is an object of the present invention toprovide an insulation shredding apparatus for generating blow-ininsulation from scrap insulation.

An additional object of the present invention to provide an insulationshredding apparatus that is compact for mobility to and around areprocessing site.

A further object of the invention is to provide an insulation shreddingmethod and apparatus that is inexpensive.

Another object of the invention is to provide an insulation shreddingapparatus that accepts a wide range of insulation scrap sizes.

Yet another object of the invention is to provide an insulationshredding apparatus and method capable of packaging the shreddedinsulation.

A preferred apparatus for shredding insulation comprises a housing withan insulation inlet. A blade assembly is positioned within the housingadjacent the inlet. The blade assembly rotates about an axis defining aninsulation flow direction. The blade assembly has a plurality of knifeblades that are arranged in a helix about the axis and are operable tocatch insulation inserted through the inlet. An obstruction member isconnected to the housing adjacent the blade assembly. The obstructionmember obstructs the insulation caught on the rotating blade assembly sothat the knife blades shred the insulation. The helical arrangement ofthe knife blades urges shredded insulation along the flow direction.

The shredding apparatus may also include an inlet flow regulator thatfeeds the insulation into the housing at a selected rate, and an augerpositioned within the housing coaxial with the blade assembly to receiveshredded insulation from the blade assembly and to discharge theshredded insulation from the apparatus.

A preferred method of the invention includes feeding insulation scrapstoward a rotating blade assembly, catching the fed insulation with theblade assembly, obstructing the insulation caught on the rotating bladeassembly so that the blade assembly shreds the insulation, and urgingthe shredded insulation along a horizontal flow axis.

The foregoing additional features and advantages of the presentinvention will be more readily apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an insulation shredder apparatus of thepresent invention, with a guard for covering the pulleys and beltsremoved.

FIG. 2 is an end view of the insulation shredding apparatus of FIG. 1,with interior components shown in dashed lines.

FIG. 3 is a cutaway, partial cross-sectional front view of theinsulation shredding apparatus of the present invention, showinginterior components of the apparatus.

FIG. 4 is a sectional view generally taken along line 4--4 of FIG. 3.

FIG. 5 is an enlarged cross-sectional view generally taken along line5--5 of FIG. 4.

FIG. 6 is an enlarged cutaway view taken along line 6--6 of FIG. 3.

DESCRIPTION OF A PREFERRED EMBODIMENT

An insulation shredding apparatus in accordance with a preferredembodiment of the present invention is designated in FIG. 1 withreference numeral 10. The shredding apparatus generally includes ahousing 14 supported on a frame 12, with a feed hopper 16 mounted uponthe housing 14. In operation, insulation to be shredded is fed into thefeed hopper 16 defining a chute into the machine. The insulation dropsthrough the bottom of the feed hopper into a dual-roller feed regulator18 (see FIGS. 2 and 4). The feed regulator 18 feeds the insulation at apreselected rate toward a blade assembly 20 that rotates about ahorizontal axis 21 within the housing 14.

The blade assembly 20 catches the insulation and rotates the insulationto a stator 22 (obstruction member). The stator has fixed teethinterdigitated with the rotor blades to provide cross-combing actioncausing the blade assembly 20 to shred the insulation. As shown in FIG.3, as the blade assembly 20 rotates, it progressively urges the shreddedinsulation in a flow direction 23 parallel to axis 21 toward an auger24. The auger 24 rotates coaxially with the blade assembly 20 and movesthe insulation in the flow direction 23 to discharge the insulationthrough an insulation outlet 26 in the housing 14.

As shown in FIG. 3, the housing 14 has a lower cylindrical housingportion 28 and an upper feed portion 30. The cylindrical housing 28 isan elongate tube that closely houses the blade assembly 20 and auger 24.The cylindrical housing 28 is positioned on top of the support frame 12such that the portion housing the auger 24 is substantially cantileveredfrom the frame 12. The housing upper feed portion 30 encloses the feedregulator 18, which is positioned directly above the blade assembly 20.

One end of the housing 14 is defined by a first end plate 36 thatencloses a first end of the feed portion 30 and the cylindrical housing28. A second end plate 38 encloses the opposite second end of the feedportion 30, and has a circular aperture on a lower portion thereof. Theaperture permits passage of material from the rotor to the auger, andframes the cylindrical housing 28 near the intersection of the bladeassembly 20 and auger 24. As shown in FIGS. 1 and 2, the first andsecond end plates 36, 38 each have a pair of attachment flanges 40 forattaching the housing to the frame 12. The attachment flanges 40 extendfrom the underside of the cylindrical housing 28. The attachment flanges40 have bolt holes that align with bolt holes on respective pairs ofattachment plates 42 that extend vertically from the frame 12. Tominimize apparatus vibration, resilient washers 44 are sandwichedbetween the attachment flanges 40 and the attachment plates 42.Attachment bolts 46 are received through the bolt holes and washers 44.

As shown in FIG. 2, the frame 12 and housing 14 together define a frontside 48 and a back side 50 of the shredding apparatus 10. To increasethe mobility of the shredding apparatus, the frame 12 may be equippedwith wheels (not shown).

As shown in FIG. 2, the hopper 16 extends upwardly from an upper side 52of the housing feed portion 30. The hopper 16 is tilted from thevertical toward the front side 48 of the apparatus 10. The hopper isupwardly flared, with a rectangular cross-section that gradually widenswith elevation to a top rectangular feed opening 56. The feed opening 56is conveniently positioned about six feet above the ground level and islarge enough to receive varying sizes of scrap insulation. The frontedge of the feed opening 56 has a smooth, downwardly curved lip 58 toprevent insulation from snagging when fed into the hopper. The hopper 16may be spot-welded or attached with fasteners or other means to thehousing.

Insulation scraps placed in the hopper 16 enter the housing through afeed opening 59 where the lower end of the hopper meets the upper side52 of the housing (see FIG. 4). The feed regulator 18 is positioneddirectly below the feed opening 59 and comprises two parallel, elongaterollers 60a, 60b that extend parallel with the axis 21. The rollerscounter-rotate to draw the insulation between them, and thereby to feedinsulation into the cylindrical housing 28 at a predetermined rate. Therollers 60a, 60b include central shafts 62a, 62b with first and secondshaft ends 64, 66 that extend from the opposite ends of the rollers.

A large opening 65 defined in the housing first end plate 36 (see FIG.2) receives the rollers 60a, 60b. As shown in FIG. 3, the second end 66of each shaft is received in a shaft aperture 68 defined in the housingsecond end plate 38. A bearing ring 70 rotatably supports the secondshaft end 66 within the shaft aperture. The bearing ring 70 has aperipheral attachment flange 72 that is bolted to the exterior of thesecond end plate 38, and an inner bearing surface to permit the smoothrotation of the shafts 60a, 60b.

The first shaft ends 64 are secured by a flange plate assembly 74 (seeFIGS. 2 and 3). The flange plate assembly includes a plate 76 defining apair of shaft apertures 78, each of which receives the first end 64 of arespective one of the shafts. The plate 76 is secured to the exterior ofthe first end plate 36 by a flange plate 80. The flange plate 80 has aninner flange 81 that cradles the periphery of the plate 76. Flange plate80 has an outer peripheral attachment flange 82 that is bolted to theexterior of the first end plate 36 to secure the entire flange plateassembly 74 thereto. Bearing rings 84, which may be identical to bearingrings 70, receive the shaft first ends 64 and are bolted onto the plate76 to rotatably secure the first shaft ends 64.

As best seen in FIG. 4, the rollers 60a, 60b are separated byapproximately a one-inch gap 85. The rollers preferably have a rubberouter layer 86 with a coefficient of friction that effectively grips theinsulation in the hopper 16 and pulls the insulation into compressionthrough the counter-rotating rollers 60a, 60b. It is to be understoodthat a variety of roller coatings that effectively grip may work equallyas well.

As best shown in FIG. 2, the rollers 60a, 60b are driven by a singlefeed chain 88. The feed chain 88 is driven by a feed motor 90 that ismounted on the front side 48 of the housing 14. A horizontal driveshaft91 extends from the feed motor and rotatably supports a feed pulley 92in a vertical plane spaced outward and adjacent from the first end plate36. Roller pulleys 94a, 94b are mounted on the shaft first ends 64 inplanar registration with the feed pulley 92. The feed chain 88 extendsfrom the underside of the feed pulley 92 to the underside of the firstroller pulley 94a (adjacent the apparatus' back side 50). The feed chain88 loops around the first roller pulley 94a, crosses between the rollerpulleys, loops around the underside of second roller pulley 94b, andcrosses to the upper side of the feed pulley 92. As the feed chain 88runs in the direction from the feed pulley 92 to the first roller pulley94a, the first and second roller pulleys 94 a, 94b inwardlycounter-rotate.

As shown in FIGS. 3 and 4, a rotatable driveshaft 100 extends along axis21 through the center of the cylindrical portion 28 of the housing. Thedriveshaft 100 carries the blade assembly 20 adjacent a shaft first end103 (directly below the feed regulator 18 see FIG. 2) and carries theauger 24 adjacent a shaft second end 104 (see FIG. 3). The bladeassembly 20 includes a cylindrical blade tube 108 concentrically mountedover the driveshaft 100. The blade tube 108 supports a series of knifeblades 114. The blade tube 108 is preferably rigidly welded to thedriveshaft 100 at end disk plates 112 (see FIG. 5). The blade tube 108may alternatively be mounted to the driveshaft 100 by bolts or otherfasteners.

As shown in FIGS. 3 and 4, the series of knife blades 114 are preferablyarranged in a double helical pattern along the blade tube 108. Theblades 114 project radially from the blade tube 108 and catch theinsulation fed through the feed regulator 18. As best shown in FIGS. 5and 6, the blades are planar elements, each with a leading sharpenedcutting edge 116, a sharpened distal edge 118, and a trailing edge 120.Preferably, the blades 114 are each offset about ten degrees from theperpendicular to the axis 21, such that the cutting edges 116 arepositioned relatively further in the flow direction 23 than are theblade trailing edges 120 i.e., blades 114 are each rotated about tendegrees about a radial line 114(a) drawn from axis 21 through eachblade. In the illustrated embodiment, blades 114 are rotated clockwiseinasmuch as blade tube 108 is itself rotated counterclockwise. Clockwiseis defined as when looking inwardly from distal edge 118 along radialline 114a towards axis 21. See FIGS. 3, 5 and 6. Such a blade offsetangle slows the flow of insulation through the blade assembly 20. Ingeneral, the greater the offset, the slower the insulation flow rate.

As shown in FIGS. 4, 5 and 6 the blade tube 108 has blade attachmentplates 122 for mounting the blades 114. The blade attachment plates 122extend radially from the blade tube, and each has a pair of bolt holes126 that align with a corresponding pair of bolt holes in each blade(see FIG. 6). Pairs of bolts 128 (see FIG. 5) secure the blades 114 tothe attachment plates 122. The attachment plates 122 are preferablywelded to the blade tube 108 and are offset as described above to offsetthe blades 114.

The blade assembly 20 rotates in a direction shown by directional arrow121 in FIGS. 3, 4 and 6. The rotation of the blade assembly rotates eachblade 114 through a circular path. The rotating double helical patternof blades 114 urges insulation to flow in the flow direction 23 (seeFIG. 3), in spite of the contrary forces generated by the angled blades.A narrow gap 119 separates the blade distal edges 118 and the interiorof the cylindrical housing 28 so that the helical blade arrangementurges the insulation in an auger-like action along flow direction 23. Toincrease the insulation flow rate, the blade offset angle could bereversed such that the cutting edges are offset behind the trailingedges (not shown). The blades set in such a reverse offset angletogether are contoured more like a true helical auger, and so increasethe flow speed of the insulation.

As shown in FIGS. 3 and 4, the stator 22 is positioned within thehousing adjacent the blade assembly 20. The stator 22 obstructs theinsulation caught on the rotating blade assembly 20 so that the bladeassembly shreds the insulation. As seen in detail in FIG. 5, the statorhas a body 130 that extends parallel with the axis 21 along the bladeassembly. The stator 22 is positioned adjacent an upper portion of theblade assembly 20, on the side of the blade assembly where the bladesare rotating downwardly (see directional arrow 121 in FIG. 4). As shownin FIG. 5, the stator body 130 is closely spaced from the blade topedges 118, and has block-like stator fingers or extensions 132 that areinterdigitated with the blade assembly blades 114. Both the stator body130 and stator fingers 132 obstruct the insulation caught on the bladeassembly 20 so that the blade assembly shreds the insulation in across-combing action.

While the stator fingers 132 are block-like in the preferred embodiment,the extensions could also be sharpened to contribute to thecross-combing shredding of insulation.

As shown in FIG. 4, the stator 22 is mounted through an elongate slot129 in an upper part of the back side 50 of the cylindrical housing 28.The elongate stator body 130 snugly fits within the slot. The stator 22has three stator flanges 131 for mounting the stator to the housing (oneof which is shown in FIGS. 4 and 5). The stator flanges 131 extenddownwardly from the stator body 130. Each flange 131 has a single bolthole 133 that aligns with a threaded hole in the cylindrical housing 28.A stator bolt 134 is received in the aligned holes to secure the stator22 in position.

The shredding apparatus 10 of the present invention is configured topermit repeated shredding of a given scrap of insulation before theinsulation enters the auger 24. After the insulation is shredded at thejunction of the stator 22 and blade assembly 20, the insulation may falloff the blade assembly 20 into a lower portion of the cylindricalhousing 28. Such shredded insulation may be recaught by the bladeassembly 20 and rotated upward to the stator 22 for reshredding. Thepreferred offset of the blade assembly blades 114, as discussed above,contributes to the repeated shredding of insulation by slowing the flowrate of insulation through the blade assembly 20.

Alternatively, insulation may cling to the blades 114 after theinsulation has been shredded at the stator 22. In this case, theshredded insulation moves with the blade 114 through another revolutionof the blade assembly 20 to be reshredded at the stator 22.

As best shown in FIG. 3, the auger 24 is mounted on the driveshaft 100directly adjacent and downstream from the blade assembly 20. The augerincludes an auger blade 146 formed in a continuous helical shape. Theauger blade 146 is separated from the inside of the cylindrical housingby a narrow gap 147. The auger 24 receives shredded insulation from theblade assembly 20 and rotates about the axis 21 to move the insulationin the flow direction 23 toward the housing outlet 26. The auger 24lightly compacts the shredded insulation while moving the insulation.

The shredded insulation is discharged from the apparatus 10 at thehousing outlet 26. As shown in FIG. 1, a bag 148 (or other receptacle)may be positioned at the outlet 26 to receive the insulation. The bag148 may be secured around the cylindrical housing 28 adjacent the outlet26 by a rubber band 150, or the like. In this way, the shreddedinsulation may be packaged at the construction site. Since the shreddingapparatus 10 does not rely on air flow to urge the shredded insulationfrom the housing, the bag 148 may be impermeable to air.

To mount the driveshaft 100 (with the blade assembly 20 and auger 24mounted thereon) within the cylindrical housing 28, the shaft 100 may beinserted through the housing outlet 26. The first shaft end 103 isreceived through a shaft aperture 135 in the first end plate 36 (seeFIG. 3). A shaft bearing ring 136 receives and rotatably supports thefirst shaft end. The shaft bearing ring 136 has a peripheral flange 138that is rigidly bolted to the exterior of the first end plate 36.

The second driveshaft end 104 is rotatably attached to a verticalsupport bar 140 that is fixed within the cylindrical housing 28 adjacentthe auger 24. The support bar 140 is fixed within the cylindricalhousing by pairs of bolts 142 passing respectively through the top andbottom of the cylindrical housing 28. The driveshaft second end 104 hasa cylindrical bearing cavity 143 that receives a cylindrical bearingstud 144 that extends from the center of the shaft support bar 140.

As best shown in FIGS. 1 and 2, a drive motor 152 powers the driveshaft100 to rotate the blade assembly 20 and auger 24. The drive motor 152 ismounted upon a lower shelf 154 of the frame 12. A drive pulley 156mounts upon a horizontal drive motor shaft 157. A driveshaft pulley 160mounts on the driveshaft first end 103 in planar registration with thedrive pulley 156. A single drive belt 162 connects the drive pulley 156and driveshaft pulley 160 to rotate the driveshaft 100. As shown in FIG.3, a removable guard 163 covers the belt, chain and pulleys associatedwith the feed and drive motors.

Example

In a preferred embodiment, the feed motor 90 is a single-phased,220-volt, one-sixth horsepower "Maxi Torq Premium" motor made by DaytonMotors Company. The feed pulley 92 and roller pulleys 94a, 94b are sizedfor a three-to-one mechanical gear reduction. The feed motor 90 ispreferably run at 30 rpm to counter-rotate the rollers 60a, 60b at arate of 10 rpm. Other feed motor types, roller sizes and rollercounter-rotation speeds may also work equally as well.

The knife blades 114 are Kondex Company 573BB3R1 half-section knives.Forty-two blades are mounted on the blade tube 108, with 21 blades ineach helical pattern. The blades 114 have a longitudinal spacing ofabout 1.5 inches along the blade tube 108. Other kinds of blades, bladepatterns, numbers of blades, and blade spacing may work equally as well.For instance, a single helical pattern of blades 114 may be used.

The auger blade 146 preferably is about 0.25 inch thick, with about a12-inch outer diameter and an 8.5-inch pitch. The auger blade 146 iswelded to the driveshaft 100, which preferably has an outer diameter ofabout 2.875 inches. Various other auger pitches and blade types willwork equally as well.

The drive motor 152 is a single-phase, 220-volt, three-horsepower "UCMotor Series 2000" motor made by the WEG Company. The drive motor has afive-tone ratio reduction gear box, and the pulleys 157, 160 have aone-to-one mechanical ratio. The drive motor 152 rotates at 1,750 rpm torotate the driveshaft at about 350 rpm. Various other drive motor types,motor speeds and pulley sizes may be used with equally good results.

The drive motor 152 and pulley motor 90 are both controlled by a singleswitch on control box 164 to run at the preselected speeds (see FIG. 1).

This exemplary shredding apparatus generally shreds insulation into 1-to 2-inch-diameter pieces. The resulting mean size is adjustable. Forinstance, the mean size may be increased by wider spacing of the knifeblades 114, and by reversal of the preferred blade offset angle. Thecontrol box 164 could also be equipped to selectively vary the motorspeeds which could permit insulation to be shredded in customized sizes.

The shredding apparatus may be used to shred scrap insulation at aconstruction site, a centralized reprocessing site where scrapinsulation is collected, an insulation factory, or other sites.

Having illustrated and described the principles of the invention in apreferred embodiment, it should be apparent to those skilled in the artthat the invention can be modified in arrangement and detail withoutdeparting from the such principles. I claim all modifications comingwithin the spirit and scope of the following claims.

I claim:
 1. A machine for shredding material, comprising:a housinghaving an inlet for the material; a blade assembly positioned within thehousing adjacent the inlet, the blade assembly being rotatable about anaxis defining a flow direction for the material, whereby rotation of theblade assembly induces material fed through the inlet to the housing toflow along the axis towards one end of the blade assembly, the bladeassembly having a plurality of generally radially extending knife bladesarranged in a helix about the axis, the knife blades each beingrelatively planar and having a leading cutting edge and a trailing edge,each of the knife blades being disposed generally transversely to theaxis but being rotated about a radial line drawn from the axis throughthe blade such that the cutting edge of the blade is positionedrelatively further toward the one end of the blade assembly than is thetrailing edge thereof, the blade assembly being operable to catch thematerial fed into the housing and move it in the flow direction, therotated trailing edges of the knife blades serving to decrease the speedof movement of the material in the flow direction; and an obstructionmember connected to the housing adjacent the blade assembly, theobstruction member comprising a fixed member having fingersinterdigitated with the blades of the blade assembly, the obstructionmember obstructing the insulation caught on the rotating blade assembly,whereby the blades shred the material.
 2. A machine according to claim1, wherein each of the knife blades is rotated about ten degrees aboutthe radial line.